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The Food and Drug Administration on Tuesday authorized second Covid-19 boosters for people 50 years and older.

People 50 and older are now eligible for another shot of either the Pfizer-BioNTech and Moderna mRNA vaccines four months after their last dose, the FDA said.


Health officials cited data from Israel showing that second boosters increased antibody levels, while other studies from Israel have shown that the shots increased protection against death during the country’s Omicron wave. Much of that data is considered preliminary, and it’s only been a few months since those doses started going into arms. Pfizer and BioNTech also said they submitted data to the FDA showing some waning of effectiveness three to six months out from the first booster shots.

“Current evidence suggests some waning of protection over time against serious outcomes from Covid-19 in older and immunocompromised individuals,” Peter Marks, the director of the FDA’s Center for Biologics Evaluation and Research, said in a statement. “Based on an analysis of emerging data, a second booster dose of either the Pfizer-BioNTech or Moderna Covid-19 vaccine could help increase protection levels for these higher-risk individuals.”

Later Tuesday, the Centers for Disease Control and Prevention revised its Covid-19 vaccine recommendations to match the updated FDA authorization. The CDC also said that people who received the one-dose Johnson & Johnson primary series and had received a J&J booster at least four months ago could get a second booster with one of the mRNA shots. 


The FDA on Tuesday also authorized second boosters for people with certain immunocompromising conditions. While the primary series of shots for most people is two doses of the mRNA vaccines, it’s considered three doses for people with suppressed immune systems, so this will be their fifth shot.

Health officials framed the second booster as an option that could offer older adults and people with health conditions more robust protection, but they did not urge everyone now eligible for shots to get them immediately. 

Another booster “is especially important for those 65 and older and those 50 and older with underlying medical conditions that increase their risk for severe disease from Covid-19,” CDC Director Rochelle Walensky said in a statement. 

The agencies made the decisions without calling meetings of either the FDA’s or CDC’s advisory panels of outside experts, which typically vote to recommend authorizing vaccines and for which groups they should be made available. The move will leave the administration open to criticism that it is skipping steps in the scientific and regulatory review process.

Experts have been debating when and for which age groups another round of boosters should be offered. Earlier this month, Pfizer and BioNTech asked the FDA to green-light second boosters for people 65 and older. Soon after, Moderna applied for another booster for all adults, though it said it did so to allow the CDC “flexibility” in recommending which groups should be eligible for the shots.

On a call with reporters Tuesday, Marks said the FDA landed on 50 as the age cutoff because one in three people 50 to 65 have a health condition that leaves them vulnerable to more severe Covid-19. The agency wanted to include them as well as older people. “We felt like we should capture the population that might most benefit from this,” Marks said.

The booster decision was made against a backdrop of slowing Covid progress in this country. While cases have fallen substantially since the height of the Omicron wave, some regions are seeing small upticks in infections, though they remain at overall low levels. Experts anticipate that the more transmissible BA.2 lineage of the Omicron family could ignite spikes in infections — and in turn, some increases in hospitalizations and deaths — in some parts of the country as it builds in prevalence.

Health officials have also had to consider the timing of another booster, given that the protection against infection seems to wane within months. The BA.2 trend lines — the variant is contributing to spiking cases in Europe — have alarmed some experts. And while cases nationally have peaked over the fall and winter, southern states have seen summertime waves; some forecasters think those same states could be vulnerable to another surge this summer. But it’s also possible that giving older adults a booster now might leave them vulnerable to infection come winter.

Bob Wachter, the chair of the University of California, San Francisco’s department of medicine, backed the FDA’s decision, but said that people should also consider their own situations. He said that he — a relatively healthy 64-year-old — plans to get another shot but wasn’t running out to the pharmacy immediately, but that he had told his mother to quickly make an appointment. There are minimal safety concerns with another dose for older adults, Wachter noted.

“For someone at high risk, it’s a pretty clear call,” Wachter said. “When you get to a low-risk 50 year old, it’s a little closer.”

Wachter cautioned against people waiting in anticipation of an increase in transmission later on, likening it to playing the stock market. But he did say that people who’ve been vaccinated, had their original boost, and were infected during the Omicron wave could afford to wait a few months, with that recent infection acting as the rough equivalent of another boost. 

Marks told reporters that a wider booster campaign come the fall was possible, by which point the vaccine design may be updated to better match the form of the virus that’s dominant. If health authorities decide to refine the vaccine, people who get boosters now would likely be eligible for an updated booster later on, Marks said.

While some people will eagerly roll up their sleeves once more, it does not seem there is huge immediate demand for another shot, particularly just months after the initial booster campaign. Fewer than half of people who are eligible for boosters and who had their primary series of shots have received an initial booster, CDC data show. Among those 65 and older, just 2 in 3 vaccinated people have had a booster. A primary reason the United States had a much worse Omicron wave than some European countries — in terms of hospitalizations and deaths, not just infections — was because of the country’s relatively low booster rate among older adults, who needed the third shot to maintain strong protection against a virus as mutated as Omicron.

Some countries have already authorized second boosters for older adults. The United Kingdom is offering another round of shots to people 75 and older this spring, with a wider campaign potentially planned for later on.

Israel, where much of the booster data the United States is relying on has been generated, made second boosters available to people 60 and older late last year as Omicron took off.

It’s been clear that another booster shot can top up recipients’ antibodies — which can help block infection entirely — but that levels of those immune fighters naturally fall within a few months. That can leave people susceptible to an infection again, particularly as the virus continues to evolve, though the vaccination courses seem to provide durable and strong protection against severe disease and death for most people.

Older people tend to mount less robust responses to vaccines, so it’s possible they need another dose to mount the same protection a younger adult would generate with fewer shots.

“For most people who have been vaccinated and had one booster, the original booster shot is continuing to provide you with good protection from being hospitalized or dying,” Marks told reporters.

Kathryn Edwards, the scientific director of the Vanderbilt Vaccine Research Program, said that the data on second boosters were so far limited, though the Israeli findings “suggest that a fourth dose increases the antibody responses.” She said that it’s not clear how much waning occurs and how quickly after an initial booster, particularly in the protection against severe disease, which remains the main goal of the vaccines. 

“I’m not against, it, certainly, and I probably will as an old woman go get a fourth dose,” Edwards said. “But it would be nice to have a little bit more information.”

The announcement Tuesday in some ways echoes the debate last year when boosters for adults were first authorized. Some scientists argued the Biden administration got ahead of the scientific process by detailing plans for a booster rollout before the FDA’s and CDC’s advisory panels had weighed in, and by expanding the campaign beyond what the experts had endorsed. In that case, the FDA and CDC ultimately endorsed the shots, and boosters became crucial with the emergence of the Omicron variant.

In this case, neither the FDA’s nor the CDC’s advisory panels met to weigh second boosters ahead of the administration’s decision. Marks said the FDA moved ahead with another shot without calling a meeting of its vaccines advisory committee because it was a “relatively straightforward decision” that was clear based on available data.

The FDA had already scheduled a meeting of that committee for next Wednesday to have a general discussion about fourth shots. The announcement of the meeting said that the panel would help the FDA develop a “framework that will inform its regulatory decision-making” on the “timing and populations for Covid-19 vaccine booster doses in the coming months.” It also says that “no vote is planned at this meeting and there will not be any discussion of any product-specific applications.”

Administration officials say they have purchased enough supply to provide fourth doses to older adults this spring, but have warned they’re lacking the funds to make boosters accessible and free for the general population later on should the shots be necessary. The White House has been warning that Congress needs to authorize more funding so the government can keep offering free Covid testing, therapeutics, and shots, while lawmakers are still negotiating a funding plan.

This story has been updated with additional comments. 

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